It may be the only one. I was simply aware of this example. My point is not that Jitsi cannot be selfhosted but that using it in your client means your client requires a full web rendering engine to provide that feature, making clients more resource-hungry. To be clear, i'm great it exists at all. It has provided useful services for tech conferences like FOSDEM. I'm just concerned with interoperability and the webification of everything.
Using HTTPS for transport as part of the matrix protocol is great for punching through firewalls, i'm just not convinced the rest of the web stack is well-suited to social networking usecases with a lot of information pouring in. Web engines and the DOM model were designed for static data, not for highly-dynamic information, although there's ongoing R&D around virtual DOMs to optimize those usecases.
Is there any other example than Jitsi? I thought that was the only third party integrated in the core, and even that can be self-hosted.